<div class="iteye-blog-content-contain" style="font-size: 14px"><p><div id="cnblogs_post_body"></p>
<p> <p><span style="font-size: 16px">1. 什么是协程?</span></p> </p>
<p> <p><span style="font-size: 16px"> 协程(coroutine),又称微线程。协程不是线程也不是进程,它的上下文关系切换不是由CPU控制,一个协程由当前任务切换到其他任务由当前任务来控制。一个线程可以包含多个协程,对于CPU而言,不存在协程这个概念,<strong>它是一种轻量级用户态线程(即只针对用户而言)</strong>。协程拥有自己的寄存器上下文和栈,协程调度切换到其他协程时,将寄存器上下文和栈保存,在切回到当前协程的时候,恢复先前保存的寄存器上下文和栈。</span></p> </p>
<p> <p><span style="font-size: 16px">2. 在编程中为什么要使用协程?</span></p> </p>
<p> <p><span style="font-size: 16px"> 使用协程的好处:(1)CPU无需负担上下文的开销;(2)不需加锁(多个线程操作数据时得加锁);(3)由程序员切换控制流,方便编程;(4)</span><span style="font-size: 16px">高并发、高扩展、低成本(一个CPU支持上万的协程都不是问题)。</span></p> </p>
<p> <p> &nbsp;<span style="font-size: 16px">当然,任何事物有优点必有缺点。协程得缺点:(1)协程自己无法利用CPU多核资源(除非与多进程或者多线程配合);(2)遇到阻塞操作会使整个程序阻塞。</span></p> </p>
<p> <p>&nbsp;</p> </p>
<p> <p><span style="font-size: 16px">例一(使用yield实现在任务间的切换):</span></p> </p>
<p> <div class="cnblogs_code"></p>
<p> <img id="code_img_closed_868047cc-5571-4a37-9978-938f91cb06d2" class="code_img_closed" src="http://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif" alt="" /></p>
<p> <img id="code_img_opened_868047cc-5571-4a37-9978-938f91cb06d2" class="code_img_opened" style="display: none" src="http://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif" alt="" /> </p>
<p> <div id="cnblogs_code_open_868047cc-5571-4a37-9978-938f91cb06d2" class="cnblogs_code_hide"> </p>
<p> <pre><span style="color: #008080"> 1</span> <span style="color: #0000ff">import</span><span style="color: #000000"> time</p>
<p></span><span style="color: #008080"> 2</span> </p>
<p><span style="color: #008080"> 3</span> <span style="color: #0000ff">def</span><span style="color: #000000"> func1(name):</p>
<p></span><span style="color: #008080"> 4</span> <span style="color: #0000ff">print</span>(<span style="color: #800000">&quot;</span><span style="color: #800000">----func1 start...----</span><span style="color: #800000">&quot;</span><span style="color: #000000">)</p>
<p></span><span style="color: #008080"> 5</span> <span style="color: #0000ff">for</span> i <span style="color: #0000ff">in</span> range(6<span style="color: #000000">):</p>
<p></span><span style="color: #008080"> 6</span> temp = <span style="color: #0000ff">yield</span> <span style="color: #008000">#</span><span style="color: #008000">每次遇到yield,func1在此处阻塞,直到temp接收到func2中con.send()传来的值</span></p>
<p><span style="color: #008080"> 7</span> <span style="color: #0000ff">print</span>(<span style="color: #800000">&quot;</span><span style="color: #800000">%s in the func1</span><span style="color: #800000">&quot;</span> %<span style="color: #000000"> (str(temp)))</p>
<p></span><span style="color: #008080"> 8</span> time.sleep(1<span style="color: #000000">)</p>
<p></span><span style="color: #008080"> 9</span> </p>
<p><span style="color: #008080">10</span> </p>
<p><span style="color: #008080">11</span> <span style="color: #0000ff">def</span><span style="color: #000000"> func2():</p>
<p></span><span style="color: #008080">12</span> <span style="color: #0000ff">print</span>(<span style="color: #800000">&quot;</span><span style="color: #800000">----func2 start...----</span><span style="color: #800000">&quot;</span><span style="color: #000000">)</p>
<p></span><span style="color: #008080">13</span> con.<span style="color: #800080">__next__</span>() <span style="color: #008000">#</span><span style="color: #008000">此处开始真正的func1的调用</span></p>
<p><span style="color: #008080">14</span> <span style="color: #0000ff">for</span> i <span style="color: #0000ff">in</span> range(5<span style="color: #000000">):</p>
<p></span><span style="color: #008080">15</span> con.send(i+1<span style="color: #000000">)</p>
<p></span><span style="color: #008080">16</span> <span style="color: #0000ff">print</span>(<span style="color: #800000">&quot;</span><span style="color: #800000">%s in the func2</span><span style="color: #800000">&quot;</span> %<span style="color: #000000"> i)</p>
<p></span><span style="color: #008080">17</span> </p>
<p><span style="color: #008080">18</span> </p>
<p><span style="color: #008080">19</span> <span style="color: #0000ff">if</span> <span style="color: #800080">__name__</span> == <span style="color: #800000">'</span><span style="color: #800000">__main__</span><span style="color: #800000">'</span><span style="color: #000000">:</p>
<p></span><span style="color: #008080">20</span> con = func1(1) <span style="color: #008000">#</span><span style="color: #008000">在有yield的函数中此处不是真正的函数调用,打印con便可知道</span></p>
<p><span style="color: #008080">21</span> <span style="color: #008000">#</span><span style="color: #008000"> print(con)</span></p>
<p><span style="color: #008080">22</span> p = func2()</pre> </p>
<p> </div> </p>
<p> <span class="cnblogs_code_collapse">使用yield进行任务切换</span></p>
<p> </div> </p>
<p> <p><span style="font-size: 15px"> 注:例一严格来说不能算是协程,只是实现了两个任务之间的切换。</span></p> </p>
<p> <p>&nbsp;</p> </p>
<p> <p><span style="font-size: 16px">3. 既然例一不能算多协程,难么在
PYTHON中应该如何使用协程?</span></p> </p>
<p> <p><span style="font-size: 16px"> greenlet是一个用C实现的协程模块,相比与
PYTHON自带的yield,它可以使你在任意函数之间随意切换,而不需<strong>把这个函数先声明为generator</strong>(例一中的con=func1(1)就是做这个操作)。</span></p> </p>
<p> <p>&nbsp;</p> </p>
<p> <p><span style="font-size: 16px">例二:</span></p> </p>
<p> <div class="cnblogs_code"></p>
<p> <img id="code_img_closed_f0929bd7-dab0-49a3-8a44-d97faf62506a" class="code_img_closed" src="http://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif" alt="" /></p>
<p> <img id="code_img_opened_f0929bd7-dab0-49a3-8a44-d97faf62506a" class="code_img_opened" style="display: none" src="http://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif" alt="" /> </p>
<p> <div id="cnblogs_code_open_f0929bd7-dab0-49a3-8a44-d97faf62506a" class="cnblogs_code_hide"> </p>
<p> <pre><span style="color: #008080"> 1</span> <span style="color: #0000ff">import</span><span style="color: #000000"> greenlet</p>
<p></span><span style="color: #008080"> 2</span> </p>
<p><span style="color: #008080"> 3</span> <span style="color: #0000ff">def</span><span style="color: #000000"> func1():</p>
<p></span><span style="color: #008080"> 4</span> <span style="color: #0000ff">for</span> i <span style="color: #0000ff">in</span> range(1,6<span style="color: #000000">):</p>
<p></span><span style="color: #008080"> 5</span> <span style="color: #0000ff">print</span><span style="color: #000000">(i)</p>
<p></span><span style="color: #008080"> 6</span> g2.switch() <span style="color: #008000">#</span><span style="color: #008000">切换到g2</span></p>
<p><span style="color: #008080"> 7</span> </p>
<p><span style="color: #008080"> 8</span> <span style="color: #0000ff">def</span><span style="color: #000000"> func2():</p>
<p></span><span style="color: #008080"> 9</span> words = [<span style="color: #800000">'</span><span style="color: #800000">a</span><span style="color: #800000">'</span>, <span style="color: #800000">'</span><span style="color: #800000">b</span><span style="color: #800000">'</span>, <span style="color: #800000">'</span><span style="color: #800000">c</span><span style="color: #800000">'</span>, <span style="color: #800000">'</span><span style="color: #800000">d</span><span style="color: #800000">'</span>, <span style="color: #800000">'</span><span style="color: #800000">e</span><span style="color: #800000">'</span><span style="color: #000000">]</p>
<p></span><span style="color: #008080">10</span> <span style="color: #0000ff">for</span> w <span style="color: #0000ff">in</span><span style="color: #000000"> words:</p>
<p></span><span style="color: #008080">11</span> <span style="color: #0000ff">print</span><span style="color: #000000">(w)</p>
<p></span><span style="color: #008080">12</span> g1.switch() <span style="color: #008000">#</span><span style="color: #008000">切换到g1</span></p>
<p><span style="color: #008080">13</span> </p>
<p><span style="color: #008080">14</span> g1 =<span style="color: #000000"> greenlet.greenlet(func1)</p>
<p></span><span style="color: #008080">15</span> g2 =<span style="color: #000000"> greenlet.greenlet(func2)</p>
<p></span><span style="color: #008080">16</span> g1.switch() <span style="color: #008000">#</span><span style="color: #008000">切换到g1</span></pre> </p>
<p> </div> </p>
<p> <span class="cnblogs_code_collapse">使用greenlent模块实现任务切换</span></p>
<p> </div> </p>
<p> <p> <span style="font-size: 15px">注:使用greenlent可以很简单的进行多任务之间的切换,但是程序运行最耗时的便是I/O操作,要使用协程实现高并发,应当是<strong>一旦遇到I/O操作就切换到其他任务,等I/O操作完成后在切回到当前任务(这个过程应当是自动的)。</strong></span></p> </p>
<p> <p>&nbsp;</p> </p>
<p> <p><span style="font-size: 16px">4. 那么在
PYTHON中,如何让任务遇到I/O操作就切换?</span></p> </p>
<p> <p><span style="font-size: 16px"> 我们使用第三方库gevent来实现。</span></p> </p>
<p> <p><span style="font-size: 16px"> gevent的官方定义:gevent is a&nbsp;<a class="reference external" href="https://en.wikipedia.org/wiki/Coroutine">coroutine</a>&nbsp;-based&nbsp;<a class="reference external" href="http://
PYTHON.org/">
PYTHON</a>&nbsp;networking library that uses&nbsp;<a class="reference external" href="https://greenlet.readthedocs.io/">greenlet</a>&nbsp;to provide a high-level synchronous API on top of the libev event loop.</span></p> </p>
<p> <p>&nbsp;</p> </p>
<p> <p><span style="font-size: 16px">例三(gevent的简单使用):</span></p> </p>
<p> <div class="cnblogs_code"></p>
<p> <img id="code_img_closed_26c74430-ff34-4e2e-af26-e8a3c235b1f0" class="code_img_closed" src="http://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif" alt="" /></p>
<p> <img id="code_img_opened_26c74430-ff34-4e2e-af26-e8a3c235b1f0" class="code_img_opened" style="display: none" src="http://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif" alt="" /> </p>
<p> <div id="cnblogs_code_open_26c74430-ff34-4e2e-af26-e8a3c235b1f0" class="cnblogs_code_hide"> </p>
<p> <pre><span style="color: #008080"> 1</span> <span style="color: #0000ff">import</span><span style="color: #000000"> gevent</p>
<p></span><span style="color: #008080"> 2</span> <span style="color: #0000ff">import</span><span style="color: #000000"> time</p>
<p></span><span style="color: #008080"> 3</span> </p>
<p><span style="color: #008080"> 4</span> <span style="color: #0000ff">def</span><span style="color: #000000"> func1():</p>
<p></span><span style="color: #008080"> 5</span> <span style="color: #0000ff">print</span>(<span style="color: #800000">&quot;</span><span style="color: #800000">func1: start.....</span><span style="color: #800000">&quot;</span><span style="color: #000000">)</p>
<p></span><span style="color: #008080"> 6</span> <span style="color: #008000">#</span><span style="color: #008000"> Put the current greenlet to sleep for at least *seconds*.(模拟I/O操作,任务在此处自动切换)</span></p>
<p><span style="color: #008080"> 7</span> gevent.sleep(3<span style="color: #000000">)</p>
<p></span><span style="color: #008080"> 8</span> <span style="color: #0000ff">print</span>(<span style="color: #800000">&quot;</span><span style="color: #800000">func1: end</span><span style="color: #800000">&quot;</span><span style="color: #000000">)</p>
<p></span><span style="color: #008080"> 9</span> </p>
<p><span style="color: #008080">10</span> <span style="color: #0000ff">def</span><span style="color: #000000"> func2():</p>
<p></span><span style="color: #008080">11</span> <span style="color: #0000ff">print</span>(<span style="color: #800000">&quot;</span><span style="color: #800000">func2: start.....</span><span style="color: #800000">&quot;</span><span style="color: #000000">)</p>
<p></span><span style="color: #008080">12</span> gevent.sleep(0.5<span style="color: #000000">)</p>
<p></span><span style="color: #008080">13</span> <span style="color: #0000ff">print</span>(<span style="color: #800000">&quot;</span><span style="color: #800000">func2: end</span><span style="color: #800000">&quot;</span><span style="color: #000000">)</p>
<p></span><span style="color: #008080">14</span> </p>
<p><span style="color: #008080">15</span> start_time =<span style="color: #000000"> time.time()</p>
<p></span><span style="color: #008080">16</span> <span style="color: #008000">#</span><span style="color: #008000"> joinall(greenlets, timeout=None, raise_error=False, count=None)</span></p>
<p><span style="color: #008080">17</span> <span style="color: #008000">#</span><span style="color: #008000"> Wait for the ``greenlets`` to finish.</span></p>
<p><span style="color: #008080">18</span> <span style="color: #008000">#</span><span style="color: #008000"> :return: A sequence of the greenlets that finished before the timeout (if any)expired.</span></p>
<p><span style="color: #008080">19</span> <span style="color: #000000">gevent.joinall([gevent.spawn(func1),</p>
<p></span><span style="color: #008080">20</span> <span style="color: #000000"> gevent.spawn(func2)])</p>
<p></span><span style="color: #008080">21</span> <span style="color: #008000">#</span><span style="color: #008000"> spawn(cls, *args, **kwargs)</span></p>
<p><span style="color: #008080">22</span> <span style="color: #008000">#</span><span style="color: #008000"> Create a new :class:`Greenlet` object and schedule it to run ``function(*args, **kwargs)``.</span></p>
<p><span style="color: #008080">23</span> <span style="color: #008000">#</span><span style="color: #008000"> This can be used as ``gevent.spawn`` or ``Greenlet.spawn``.</span></p>
<p><span style="color: #008080">24</span> </p>
<p><span style="color: #008080">25</span> <span style="color: #0000ff">print</span>(<span style="color: #800000">&quot;</span><span style="color: #800000">cost:</span><span style="color: #800000">&quot;</span>, time.time()-<span style="color: #000000">start_time)</p>
<p></span><span style="color: #008080">26</span> <span style="color: #008000">#</span><span style="color: #008000"> 通过计算程序运行的时间可以发现程序确实是以单线程达模拟出了多任务并行的操作。</span></pre> </p>
<p> </div> </p>
<p> <span class="cnblogs_code_collapse">gevent的简单使用</span></p>
<p> </div> </p>
<p> <p>&nbsp;</p> </p>
<p> <p><span style="font-size: 16px">例四(gevent和urllib配合同时下载多个网页):</span></p> </p>
<p> <div class="cnblogs_code"></p>
<p> <img id="code_img_closed_04c7985d-8718-4d81-b37a-847a2a20e510" class="code_img_closed" src="http://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif" alt="" /></p>
<p> <img id="code_img_opened_04c7985d-8718-4d81-b37a-847a2a20e510" class="code_img_opened" style="display: none" src="http://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif" alt="" /> </p>
<p> <div id="cnblogs_code_open_04c7985d-8718-4d81-b37a-847a2a20e510" class="cnblogs_code_hide"> </p>
<p> <pre><span style="color: #008080"> 1</span> <span style="color: #0000ff">import</span><span style="color: #000000"> urllib.request</p>
<p></span><span style="color: #008080"> 2</span> <span style="color: #0000ff">import</span><span style="color: #000000"> gevent,time</p>
<p></span><span style="color: #008080"> 3</span> <span style="color: #0000ff">import</span><span style="color: #000000"> gevent.monkey</p>
<p></span><span style="color: #008080"> 4</span> </p>
<p><span style="color: #008080"> 5</span> <span style="color: #0000ff">def</span> func(url=<span style="color: #800000">&quot;&quot;</span>, filename=<span style="color: #800000">&quot;&quot;</span><span style="color: #000000">):</p>
<p></span><span style="color: #008080"> 6</span> <span style="color: #0000ff">print</span>(<span style="color: #800000">&quot;</span><span style="color: #800000">Download:%s</span><span style="color: #800000">&quot;</span> %<span style="color: #000000"> url)</p>
<p></span><span style="color: #008080"> 7</span> result = urllib.request.urlopen(url) <span style="color: #008000">#</span><span style="color: #008000">请求打开一个网页</span></p>
<p><span style="color: #008080"> 8</span> data = result.read() <span style="color: #008000">#</span><span style="color: #008000">读取内容</span></p>
<p><span style="color: #008080"> 9</span> with open(filename, <span style="color: #800000">'</span><span style="color: #800000">wb</span><span style="color: #800000">'</span>) as fp: <span style="color: #008000">#</span><span style="color: #008000">写入文档</span></p>
<p><span style="color: #008080">10</span> <span style="color: #000000"> fp.write(data)</p>
<p></span><span style="color: #008080">11</span> <span style="color: #0000ff">print</span>(<span style="color: #800000">&quot;</span><span style="color: #800000">Finish:%s</span><span style="color: #800000">&quot;</span> %<span style="color: #000000"> url)</p>
<p></span><span style="color: #008080">12</span> </p>
<p><span style="color: #008080">13</span> <span style="color: #0000ff">if</span> <span style="color: #800080">__name__</span> == <span style="color: #800000">&quot;</span><span style="color: #800000">__main__</span><span style="color: #800000">&quot;</span><span style="color: #000000">:</p>
<p></span><span style="color: #008080">14</span> <span style="color: #008000">#</span><span style="color: #008000"> Do all of the default monkey patching (calls every other applicablefunction in this module).</span></p>
<p><span style="color: #008080">15</span> <span style="color: #008000">#</span><span style="color: #008000"> 相当与做一个标记,做完此操作gevent就可以检测到此程序中所有的I/O操作</span></p>
<p><span style="color: #008080">16</span> <span style="color: #000000"> gevent.monkey.patch_all()</p>
<p></span><span style="color: #008080">17</span> </p>
<p><span style="color: #008080">18</span> async_time =<span style="color: #000000"> time.time()</p>
<p></span><span style="color: #008080">19</span> <span style="color: #000000"> gevent.joinall([</p>
<p></span><span style="color: #008080">20</span> gevent.spawn(func, <span style="color: #800000">&quot;</span><span style="color: #800000">http://www.cnblogs.com/
[url=http://www.cppentry.com/list.php?fid=77]PYTHON[/url]d-Li/p/7774497.html</span><span style="color: #800000">&quot;</span>, <span style="color: #800000">&quot;</span><span style="color: #800000">7774497.html</span><span style="color: #800000">&quot;</span><span style="color: #000000">),</p>
<p></span><span style="color: #008080">21</span> gevent.spawn(func, <span style="color: #800000">&quot;</span><span style="color: #800000">http://www.gevent.org/</span><span style="color: #800000">&quot;</span>, <span style="color: #800000">&quot;</span><span style="color: #800000">gevent.html</span><span style="color: #800000">&quot;</span><span style="color: #000000">),</p>
<p></span><span style="color: #008080">22</span> gevent.spawn(func, <span style="color: #800000">&quot;</span><span style="color: #800000">https://www.
PYTHON.org/</span><span style="color: #800000">&quot;</span>, <span style="color: #800000">&quot;</span><span style="color: #800000">
PYTHON.html</span><span style="color: #800000">&quot;</span><span style="color: #000000">),</p>
<p></span><span style="color: #008080">23</span> <span style="color: #000000"> ])</p>
<p></span><span style="color: #008080">24</span> <span style="color: #0000ff">print</span>(<span style="color: #800000">&quot;</span><span style="color: #800000">async download cost:</span><span style="color: #800000">&quot;</span>, time.time()-<span style="color: #000000">async_time)</p>
<p></span><span style="color: #008080">25</span> </p>
<p><span style="color: #008080">26</span> start_time =<span style="color: #000000"> time.time()</p>
<p></span><span style="color: #008080">27</span> func(<span style="color: #800000">&quot;</span><span style="color: #800000">http://www.cnblogs.com/
[url=http://www.cppentry.com/list.php?fid=77]PYTHON[/url]d-Li/p/7774497.html</span><span style="color: #800000">&quot;</span>, <span style="color: #800000">&quot;</span><span style="color: #800000">7774497.html</span><span style="color: #800000">&quot;</span><span style="color: #000000">)</p>
<p></span><span style="color: #008080">28</span> func(<span style="color: #800000">&quot;</span><span style="color: #800000">http://www.gevent.org/</span><span style="color: #800000">&quot;</span>, <span style="color: #800000">&quot;</span><span style="color: #800000">gevent.html</span><span style="color: #800000">&quot;</span><span style="color: #000000">)</p>
<p></span><span style="color: #008080">29</span> func(<span style="color: #800000">&quot;</span><span style="color: #800000">https://www.
PYTHON.org/</span><span style="color: #800000">&quot;</span>, <span style="color: #800000">&quot;</span><span style="color: #800000">
PYTHON.html</span><span style="color: #800000">&quot;</span><span style="color: #000000">)</p>
<p></span><span style="color: #008080">30</span> <span style="color: #0000ff">print</span>(<span style="color: #800000">&quot;</span><span style="color: #800000">download cost:</span><span style="color: #800000">&quot;</span>, time.time()-start_time)</pre> </p>
<p> </div> </p>
<p> <span class="cnblogs_code_collapse">gevent和urllib配合同时下载多个网页</span></p>
<p> </div> </p>
<p> <p> 注:对上例代码稍加改造,加上对html源码的解析功能,就可以实现一个简单的多并发爬虫。</p> </p>
<p> <p>&nbsp;</p> </p>
<p> <p><span style="font-size: 16px">对<a id="cb_post_title_url" class="postTitle2" href="http://www.cnblogs.com/
[url=http://www.cppentry.com/list.php?fid=77]PYTHON[/url]d-Li/p/7598850.html">
PYTHON --- 网络编程Socket</a>中例二的socket_server2使用gevent改造就可以使其成为一个大并发的socket server。</span></p> </p>
<p> <p><span style="font-size: 16px">例五(使用gevent实现并发的socket server):</span></p> </p>
<p> <div class="cnblogs_code"></p>
<p> <img id="code_img_closed_45c1bc41-9757-42bd-8796-a6b582a5ef7c" class="code_img_closed" src="http://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif" alt="" /></p>
<p> <img id="code_img_opened_45c1bc41-9757-42bd-8796-a6b582a5ef7c" class="code_img_opened" style="display: none" src="http://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif" alt="" /> </p>
<p> <div id="cnblogs_code_open_45c1bc41-9757-42bd-8796-a6b582a5ef7c" class="cnblogs_code_hide"> </p>
<p> <pre><span style="color: #008080"> 1</span> <span style="color: #008000">#</span><span style="color: #008000">服务端</span></p>
<p><span style="color: #008080"> 2</span> <span style="color: #0000ff">import</span><span style="color: #000000"> socket</p>
<p></span><span style="color: #008080"> 3</span> <span style="color: #0000ff">import</span><span style="color: #000000"> gevent</p>
<p></span><span style="color: #008080"> 4</span> <span style="color: #0000ff">import</span><span style="color: #000000"> gevent.monkey</p>
<p></span><span style="color: #008080"> 5</span> </p>
<p><span style="color: #008080"> 6</span> <span style="color: #000000">gevent.monkey.patch_all()</p>
<p></span><span style="color: #008080"> 7</span> </p>
<p><span style="color: #008080"> 8</span> <span style="color: #0000ff">def</span><span style="color: #000000"> request_handler(conn):</p>
<p></span><span style="color: #008080"> 9</span> </p>
<p><span style="color: #008080">10</span> <span style="color: #800000">'''</span></p>
<p><span style="color: #008080">11</span> <span style="color: #800000"> Wait for an incoming connection. Return a new socket</p>
<p></span><span style="color: #008080">12</span> <span style="color: #800000"> representing the connection, and the address of the client.</p>
<p></span><span style="color: #008080">13</span> <span style="color: #800000">'''</span></p>
<p><span style="color: #008080">14</span> <span style="color: #0000ff">while</span><span style="color: #000000"> True:</p>
<p></span><span style="color: #008080">15</span> <span style="color: #008000">#</span><span style="color: #008000"> print(&quot;ok&quot;)</span></p>
<p><span style="color: #008080">16</span> data = conn.recv(1024) <span style="color: #008000">#</span><span style="color: #008000">接收信息,写明要接收信息的最大容量,单位为字节</span></p>
<p><span style="color: #008080">17</span> <span style="color: #0000ff">print</span>(<span style="color: #800000">&quot;</span><span style="color: #800000">server recv:</span><span style="color: #800000">&quot;</span><span style="color: #000000">, data)</p>
<p></span><span style="color: #008080">18</span> conn.send(data.upper()) <span style="color: #008000">#</span><span style="color: #008000">对收到的信息处理,返回到客户端</span></p>
<p><span style="color: #008080">19</span> </p>
<p><span style="color: #008080">20</span> </p>
<p><span style="color: #008080">21</span> </p>
<p><span style="color: #008080">22</span> <span style="color: #0000ff">if</span> <span style="color: #800080">__name__</span> == <span style="color: #800000">&quot;</span><span style="color: #800000">__main__</span><span style="color: #800000">&quot;</span><span style="color: #000000">:</p>
<p></span><span style="color: #008080">23</span> address = (<span style="color: #800000">&quot;</span><span style="color: #800000">localhost</span><span style="color: #800000">&quot;</span>, 6666) <span style="color: #008000">#</span><span style="color: #008000"> 写明服务端要监听的地址,和端口号</span></p>
<p><span style="color: #008080">24</span> server = socket.socket() <span style="color: #008000">#</span><span style="color: #008000"> 生成一个socket对象</span></p>
<p><span style="color: #008080">25</span> server.bind(address) <span style="color: #008000">#</span><span style="color: #008000"> 用socket对象绑定要监听的地址和端口</span></p>
<p><span style="color: #008080">26</span> server.listen() <span style="color: #008000">#</span><span style="color: #008000"> 开始监听</span></p>
<p><span style="color: #008080">27</span> </p>
<p><span style="color: #008080">28</span> <span style="color: #0000ff">while</span><span style="color: #000000"> True:</p>
<p></span><span style="color: #008080">29</span> conn, addr = server.accept() <span style="color: #008000">#</span><span style="color: #008000"> 等带新连接接入服务端,返回一个新的socket对象和地址,地址格式同前面格式</span></p>
<p><span style="color: #008080">30</span> <span style="color: #000000"> gevent.spawn(request_handler, conn)</p>
<p></span><span style="color: #008080">31</span> </p>
<p><span style="color: #008080">32</span> server.close() <span style="color: #008000">#</span><span style="color: #008000"> 关闭服务端</span></pre> </p>
<p> </div> </p>
<p> <span class="cnblogs_code_collapse">socket_server2的并发实现</span></p>
<p> </div> </p>
<p> <p>&nbsp;<span style="font-size: 16px"> 注:可使用<a id="cb_post_title_url" class="postTitle2" href="http://www.cnblogs.com/
[url=http://www.cppentry.com/list.php?fid=77]PYTHON[/url]d-Li/p/7598850.html">
PYTHON --- 网络编程Socket</a>中例二的socket_client2进行测试。</span></p></p>
<p></div></p></div>
python --- 协程编程(第三方库gevent的使用)
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